Sandbox Dreams

I want to be able to walk for ages, and then build a house. I want to be able to set up my own guilds, with their own guild halls, give out quests as though I was an NPC, and rise to rule over the continent. I want to be able to murder the king, disguise myself as his daughter, be married off by his grieving widow, and then murder the king I just married, by poisoning his books. I want to be able to run industries, and corner the market on certain goods.